Based on the morphologic and immunohistochemical features the differential diagnosis included a papillary ependymoma with elevated Ki-67 proliferative index, a metastatic moderately differentiated adenocarcinoma (unlikely given the patient's history and the immunohistochemical profile of the tumor), a papillary variant of a meningioma (unlikely given negative staining for PR) and a choroid plexus neoplasm. This evidence concerns the gene PGR and neoplasm.